Some years ago I built a rack on the back of the garage for storing canoes, at this time there are 9 there. (5 high)
1st the overhang was built, 7 half trusses cantilevered off the side, through bolted to structure inside, and sheathed with metal. The ends have a "wall" also attached to the garage wall, the ends are open at the bottom.
Then I nailed 2x6's together to make a 2 vertical posts, each are 2 -2x6's, these are on cement blocks and are lag bolted to the wall, about 8 ft apart. This carries the load and allowed me to put the "horizontal racks" anyplace vertically on the post.
The racks are 2x4's nailed together (to get the same width as the vertical post) and slightly tapered to the outer end.
The racks are hung with metal "tees" that are bolted to the rack and the post.
The tee's are flat stock, roughly 10ga by 2 1/2 wide, with a horizontal piece about 12" long welded to a vertical piece about 15" long, the tees are bolted to the posts with 3 - 3/8 bolts.
This allows the racks to be cantilevered out from the post without any bracing under them.
It was made/designed to hold 1 canoe deep, but I needed more so I extended the racks by adding 2x4's and made some spacers that I slide in at the ends after canoe are loaded. There are 4 spacers for each side and they go to the ground.
It's a pain to load with the spacers but they double the capacity and for long term storage it's fine.
Dan